Replacing . (dots) in a string with numbers

Hi i have the task to type in the following numbers111000 in a string, and then type this format in another string something ... something ...
the final string shout be the following:something 111 something 000

I think you may have to use a loop to examine each individual character of s to see if it is '.' and replace that character with successive characters from ss.
Exit the loop when the last character of either ss or s has been reached.